This invention relates to a flow passage structure formed by press-fitting a shaft member into a press-fit bore provided in a flange member so as to be opened at one axial end thereof, and thereby communicating with each of other flow passages formed in the flange member and those formed in the shaft member.
Such a flow passage structure is used for a support flange ember of a fluid joint, and a support flange of a stator member of a torque converter as disclosed in, for example, Japanese Patent Publication No. 40904/1990. An example of such a related art flow passage structure for a shaft-press-fitted flange member is shown in FIG. 5. This structure is formed by press-fitting a shaft member 210 into a press-fit bore 201 of a flange member 200 so as to communicate an oil passage 221 in a housing 220, to which the flange member 200 is fixed, and radial bores 212, which are formed in the shaft member 210, with each other via an inside-flange flow passage including radial bores 202 and axial bores 203 which are formed in the flange member 200. The inside-shaft radial bores 212 are joined to axially extending inside-shaft bores 211, and these axial bores 211, for example, the interior of a torque converter. This enables the supplying of an oil from the oil passages 221 of the housing 220 to the interior of a torque converter and the discharging of the oil from the latter to the former to be done.
When the flow passage structure is provided in this manner, the flow passage in the flange member 200 is formed by making the radial bores 202 extending from an outer circumferential surface of the flange member therethrough to the press-fit bore 201, and the axial bores 203 extending from a side surface of the flange member so as to communicate with the inside-flange radial bores 202, and closing the radial bores 202 of the flange member at the portions thereof which are on the side of an outer circumferential surface of the flange with plugs 205, and with balls 206 press-fitted into the mentioned portions of the same bores. As is understood from the above, the radial bores 202 in the flow passage structure shown in FIG. 5 are formed from the outer circumferential side of the flange, and it is therefore necessary that the radial bores 202 be closed at the outer circumferential end portions thereof with plugs 205 and press-fit balls 206. This causes a processing cost and a cost of additional parts to increase correspondingly. When the plugs 205 are employed, it is necessary that seal members be used for threaded portions thereof, and, when the press-fit balls 206 are employed, the flange member 200 requires to have a strength high enough to resist a press-fitting force. Furthermore, spaces for press-fitting the balls thereinto and inserting the plugs thereinto are needed, and, when plural radial bores 202 are formed in a certain way of arrangement, the intervals thereof have to be set large.
In view of these problems, a flow passage structure shown in FIG. 6 has also heretofore been devised. A left-hand portion of FIG. 6 shows a second flow passage structure, and a right-hand portion thereof a third flow passage structure. First, in the case of the second flow passage structure shown in the left-hand portion of FIG. 6, a communication bore 231 extending from a side surface of a flange member 230 therethrough diagonally to a press-fit bore 233 is formed, and an oil passage 221 in a housing 220 and a radial bore 212 formed in a shaft member 210 are communicated with each other via this inside-flange communication bore 231. In the case of this flow passage structure, the inside-flange communication bore 231 is formed from the side surface of the flange member 230, so that closing the bore by using a plug and a press-fit ball in an outer circumferential end portion thereof as in the structure of FIG. 5 is not necessary but an axial size A of the flange member 230 increases due to the formation of the diagonal communication bore.
In the case of the third flow passage structure shown in the right-hand portion of FIG. 6, an inside-flange flow passage is provided by forming a radial bore 242 extending from the interior of a press-fit bore 241 of a flange member 240 in the diagonal, radially outward direction, and an axial bore 243 extending from a side surface of the flange member 240 so as to communicate with the inside-flange radial bore 242. In the case of this flow passage structure, closing the bore by using a plug and a press-fit ball in outer circumferential end portions thereof as in the structure of FIG. 5 is not necessary, either. However, since the inside-flange radial bore 242 is formed from the interior of the press-fit bore 241 of the flange member 240, an angle of the inside-flange radial bore 242 is limited depending upon the size of the press-fit bore 241, so that it is difficult to form the bore 242 and reduce the dimensions of the flange member.
The present invention has been made in view of these circumstances, and provides a flow passage structure capable of forming a flow passage in a flange member easily, and a flange member compactly.
According to an aspect of the present invention, the flow passage structure for a shaft-press-fitted flange member (for example, a stator shaft 40 in a mode of embodiment) formed by press-fitting a shaft member into a press-fit bore of a flange member has a shaft member provided with first flow passages (for example, right end portions 106 of oil passages 102 in a mode of embodiment) having openings (for example, right end portions 106 of the oil passages 102 in the mode of embodiment) in an outer circumferential surface of the shaft member; and a flange member provided with blind bores (for example oil passages 101 and oil passages 105 in the mode of embodiment) formed so as to extend linearly at right angles to a shaft axis from outer circumferential surfaces (for example, outer circumferential surfaces 43b, 43c in the mode of embodiment) of the flange member and through the press-fit bore, and stop at free end portions thereof in the interior of the flange member, and communication bores (for example, oil passages 103) extending from a side surface of the flange member in the axial direction and communicating with the portions of the blind bores which extend from the press-fit bore to the free end portions thereof, second flow passages being formed of the portions (for example, the oil passages 101 in the mode of embodiment) of the blind bores which extend from the press-fit bore to the free end portions thereof and the communication bores, the shaft member being positioned so that the portions of the blind bores in the second flow passages which are opened into the press-fit bore and the first flow passages communicate with each other, and press-fitted into the press-fit bore to communicate the first and second flow passages with each other, whereby a flow passage structure is formed.
When a shaft member is press-fitted into a press-fit bore of a flange member in the case of a flow structure of such a construction, free end portions of blind bores and opposite portions (portions between an outer circumferential surface and the press-fit bore) are shut off by a shaft member press-fitted in the press-fit bore, and the free end portions communicate with openings of first flow passages formed in the shaft member. As is understood from the above, in the flow passage structure according to the present invention, only blind bores extending straight from an outer circumferential surface of the flange member in a direction (radial direction and a direction parallel thereto) which is at right angles to a shaft axis, and communication bores extending straight from a side surface of the flange member in the axial direction thereof are formed in the flange member. Namely, the forming of the flow structure can be done easily, and, since a diagonal bore is unnecessary, the flange member can be formed to a compact structure by reducing an axial size thereof.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.